Abstract: A fuel tank inerting system is disclosed. In addition to a fuel tank, the system includes a catalytic reactor with an inlet, an outlet, a reactive flow path between the inlet and the outlet, and a catalyst on the reactive flow path. The catalytic reactor is arranged to receive fuel from the fuel tank and air from an air source, and to react the fuel and air along the reactive flow path to generate an inert gas. The system also includes an inert gas flow path from the catalytic reactor to the fuel tank. The system also includes a non-uniform catalyst composition along the reactive flow path.

Abstract: A fuel tank inerting system is disclosed. In addition to a fuel tank, the system includes a catalytic reactor with an inlet, an outlet, a reactive flow path between the inlet and the outlet, and a catalyst on the reactive flow path. The catalytic reactor is arranged to receive fuel from the fuel tank and air from an air source, and to react the fuel and air along the reactive flow path to generate an inert gas. The system also includes an inert gas flow path from the catalytic reactor to the fuel tank. The system also includes a non-uniform catalyst composition along the reactive flow path.

Abstract: A fuel tank inerting system is disclosed. In addition to a fuel tank, the system includes a catalytic reactor with an inlet, an outlet, a reactive flow path between the inlet and the outlet, and a catalyst on the reactive flow path. The catalytic reactor is arranged to receive fuel from the fuel tank and air from an air source, and to react the fuel and air along the reactive flow path to generate an inert gas. The system also includes an inert gas flow path from the catalytic reactor to the fuel tank. The system also includes (a) an air distributor in the catalytic reactor arranged to distribute air along the reactive flow path, or (b) non-uniform catalyst loading or non-uniform catalyst composition along the reactive flow path, or both (a) and (b).

Abstract: A fuel tank inerting system is disclosed. In addition to a fuel tank, the system includes a catalytic reactor with an inlet, an outlet, a reactive flow path between the inlet and the outlet, and a catalyst on the reactive flow path. The catalytic reactor is arranged to receive fuel from the fuel tank and air from an air source, and to react the fuel and air along the reactive flow path to generate an inert gas. The system also includes an inert gas flow path from the catalytic reactor to the fuel tank. The system also includes (a) an air distributor in the catalytic reactor arranged to distribute air along the reactive flow path, or (b) non-uniform catalyst loading or non-uniform catalyst composition along the reactive flow path, or both (a) and (b).

Abstract: A rotary wing aircraft includes a fuselage having a plurality of surfaces, at least one engine mounted in the fuselage, and a rotor assembly including a rotor shaft and plurality of rotor blades operatively connected to the rotor shaft. The rotor assembly includes a plurality of surface portions. A rotor shaft fairing extends between the fuselage and the rotor assembly and about at least a portion of the rotor shaft. The rotor shaft fairing includes an outer surface. A plate member is mounted to and projects proudly of the at least a portion of the rotor shaft fairing. The plate member is configured and disposed to increase an aspect ratio of and reduce induced drag on the rotor shaft fairing as well as reduce rotor hub wake size.

Abstract: A rotary wing aircraft includes a fuselage having a plurality of surfaces. At least one engine is mounted in the fuselage. A rotor assembly includes a rotor shaft a plurality of rotor blades operatively connected to the rotor shaft. The rotor assembly includes a plurality of surface portions. An active air discharge opening extends through one of the plurality of surfaces of the fuselage and one of the plurality of surface portions of the rotor assembly, and an active air generation system is mounted in the fuselage. The active air generation system is configured and disposed to generate and direct a flow of air through the active air discharge opening to disrupt an airstream flowing over the one of the plurality of surfaces of the fuselage and the one of the plurality of surface portions of the rotor assembly.

Abstract: A rotary wing aircraft includes a fuselage having a plurality of surfaces, at least one engine mounted in the fuselage, and a rotor assembly including a rotor shaft and plurality of rotor blades operatively connected to the rotor shaft. The rotor assembly includes a plurality of surface portions. A rotor shaft fairing extends between the fuselage and the rotor assembly and about at least a portion of the rotor shaft. The rotor shaft fairing includes an outer surface. A plate member is mounted to and projects proudly of the at least a portion of the rotor shaft fairing. The plate member is configured and disposed to increase an aspect ratio of and reduce induced drag on the rotor shaft fairing as well as reduce rotor hub wake size.

Abstract: A rotary wing aircraft includes a fuselage having a plurality of surfaces. At least one engine is mounted in the fuselage. A rotor assembly includes a rotor shaft a plurality of rotor blades operatively connected to the rotor shaft. The rotor assembly includes a plurality of surface portions. An active air discharge opening extends through one of the plurality of surfaces of the fuselage and one of the plurality of surface portions of the rotor assembly, and an active air generation system is mounted in the fuselage. The active air generation system is configured and disposed to generate and direct a flow of air through the active air discharge opening to disrupt an airstream flowing over the one of the plurality of surfaces of the fuselage and the one of the plurality of surface portions of the rotor assembly.

Abstract: A rotary wing aircraft includes a fuselage having a plurality of surfaces, at least one engine mounted in the fuselage, and a rotor assembly including a rotor shaft, and plurality of rotor blades operatively connected to the rotor shaft. The rotor assembly includes a plurality of surface portions. A plurality of vortex generators is mounted relative to at least one of the plurality of surfaces of the fuselage and the plurality of surface portions of the rotor assembly. The plurality of vortex generators operate to disrupt a boundary layer of air flowing over the one of the plurality of surfaces and the plurality of surface portions to reduce drag on the one of the fuselage and the rotor assembly.

Abstract: A rotor hub fairing system for use in a counter-rotating, coaxial rotor system is provided including an upper hub fairing defined about an axis and a lower hub fairing defined about the axis. A shaft fairing is disposed between the upper hub fairing and the lower hub fairing. The geometry of the shaft fairing is configured to encourage a wake adjacent the upper hub fairing to form collectively with a wake adjacent the lower hub fairing.